DST to PST bug?

Was checking in on a sequence about 20 minutes after the time change (roll back one hour). The prior image finished at 1:54 am, the next 10 minute exposure started before 2:00 am. By the time I noticed it, the remaining exposure time was about 3100 seconds. I watched for a while and finally aborted the exposure. Started a new one right away and all was right with the world.